CVE-2026-40317

9.3 CRITICAL 0.2% exploit odds Fix listed Code execution OS & kernel

What it is

NovumOS is a custom 32-bit operating system written in Zig and x86 Assembly. In versions prior to 0.24, Syscall 12 (JumpToUser) accepts an arbitrary entry point address from user-space registers without validation, allowing any Ring 3 user-mode process to jump to kernel addresses and execute arbitrary code in Ring 0 context, resulting in local privilege escalation. This issue has been fixed in version 0.24. If developers are unable to immediately update, they should restrict syscall access by running the system in single-user mode without Ring 3, and disable user-mode processes by only running kernel shell with no user processes. This issue has been fixed in version 0.24.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-04-18 01:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-26 21:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 9.3 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-04-18 01:16 UTC
Last modified: 2026-10-26 21:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-20 · Improper input validation
Record status: Analyzed

Affected

minecanton209 Novumos < 0.24

Attack profile CVSS 3.1 · 9.3

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-40317.md and follow it. Check whether this project is affected by CVE-2026-40317. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record